Production of artificial threads, filaments, bands, films, or the like containing proteins



Patented Apr. 2,1940

UNITED STATES PATENT OFFICE Theodoor Koch, Oostcrbeek, Netherlands,assignor to American Enlra Corporation, Enka, N. 0.,

No Drawing; Application July 2'7, 1937, Serial 13 Claims.

This invention relates to the production of artificial threads,filaments, bands, films or the like containing proteins. It is known tospin into threads alkaline spinning solutions containing casein or otherproteins by employing spinning baths containing acid. The artificialthreads made in this way have, however, little value as substitutes fortextile fibres since they possess only very low strength. I

Attempts have been made to increase the strength of filaments preparedas described above by applying tension to the freshly formed thread by aprocess similar to that employed in the case of viscose silk orcuprammonium silk, but this method has not led to satisfactory resultssince even the application of slight tension is apt to break thethreads.

Attempts have also been made to harden the threads during the spinningoperation by the Z0 addition to the spinning bath of formaldehyde butthreads made in this way have too little stretch and furthermorespinning baths containing formaldehyde are unpleasant to work with.

Now it was found that improved threads, filaments, bands, films or thelike may be obtained from a solution containing protein by employing aglue precipitating bath containing aromatic or hydroaromatic sulfonicacids and/or condeni0 sation products of these aromatic or hydroaromaticsulfonic acids with aldehydes which substances have the property oftanning proteins.

The present invention accordingly comprises a process for the productionof artificial threads, 35 filaments, bands, films or the like containingproteins from solutions of alkali salts of protein by bringing the saidsolution into contact with an acid precipitating bath which processconsists in incorporating in the precipitating bath a proportion of asubstance which has a precipitating action on glue solutions and atanning action on the freshly produced artificial product and thereaftersubjecting the said artificial prodnot to hardening with formaldehyde orthe like. The thread, filament, band, film or the like may be subjectedto tension whiie still in the acid bath.

The tanning substances added to the precipitating bath may consist ofcondensation products of aromatic and hydroaromatic sulfonic acids andaldehydes and include in particular the water soluble methylenecompounds resultifig from the condensation of aromatic and hydroaromaticsulfonic acids or their hydroxy, amino In Germany August 4, 1936 orchlorine derivatives and the like with aldehydes for exampleformaldehyde.

After formation in the presence of the above mentioned compounds theartificial products must be subjected to the action of free aldehydes inorder to bring about the hardening of the protein.

Among the tanning substances which may be employed in the precipitatingbath, the following specific compounds may be mentioned, di-

- hydroxydiphenyl-methane-disulphonic acid (produced by the action offormaldehyde on phenolsulphonic acid), condensation products oftetrahydronaphthalenesulphonic acid with formaldehyde or other aldehydeor condensation products of amino-sulphonic acids orhydroxy-amino-sulphonic acids of the naphthalene or anthracene serieswith formaldehyde or the like. The tanning substance may also consist ofan aromatic sulphonic acid including the monoor polysulphonic acids ofaromatic or hydroaromatic hydrocarbons or of monoor polysulphonic acidsof oxygen-containing derivatives of aromatic or hydroaromatichydrocarbons. The monoor polysulphonic acids may further be employed inthe form of their compounds with aliphatic alcohols. There may also beemployed sulphonic acids of aromatic or hydroaromatic monoor polyhydroxycompounds, of keto-compounds, or of carboxylic acids. Examples of theabove substances are naphthalene-sulphonic acid, tetraline-sulphonicacid, toluene-isopropyl-sulphonic acid, phenol-sulphonic acid,cyclohexanone-sulphonic acid, benzoic-sulphonic acid and so forth. Suchsubstances have a. different action in the precipitating bath from thatof free aldehydes since they do not attack the amino groups of theprotein. 1

In practice it is not generally essential to employ the purecondensation product or the pure aromatic sulphonic acid, but theunpurified reaction product forms an effective tanning agent whenaddedto the precipitating bath.

In addition to the tanning compounds the spinning bath may also containa soluble salt or a mixture of soluble salts and these salts may includefor example the sulphates of sodium, am-

monium or zinc.

The acid concentration of the precipitating bath may vary between widelimits and this conv centration may be controlled either byneutraliscarbo-hydrates such as glycerol, sugar and the like, or mineralor organic acids.

In general, the sulphonic acids of the monoor polyhydroxy compounds havethe advantage of a higher solubility when salts are present- These addedsubstances also possess the advantage that they are simple and cheap tomanufacture, and even at lowconcentrations they have a tanning actionwhich is even superior to that of the condensation products mentionedabove. The freshly spun thread has an appreciabiy increased strength andthe rate of drawing ofi may thus be increased.

Threads, filaments, bands, films or like artificial products obtained inaccordance with the present invention are firmer than those prepared inthe normal precipitating baths sothat a higher .degree of stretching maybe applied thereto, this stretching resulting in a more pronouncedorientation of the micells and in the production of products possessinggreater strength.

' Following is a description by way of example of two methods ofcarrying the present invention into effect:

Example I A 17.5% solution of sodium caseinate is spun into a spinningbath consisting of 20% zinc sulphate, 1% sulphuric acid and 5% of theneutralised condensation product obtained by the action of half amolecule of formaldehyde on one. molecule of cresyl sulphonic acid.

The casein solution is spun with a total titre of 250 denier from aspinning nozzle having 0 holes each of a diameter of mu. After thethread has travelled through a distance of about 60 centimetres in thespinning bath a tension of for example 25 grams is allowed to act uponit and a considerable increase in strength is thereby obtained. Onspinning a solution of sodium caseinate under similar conditions butwithout the addition of the condensation product of formaldehyde andcresyl sulphonic acid to the spinning bath it is impossible to apply atension of this magnitude without breaking the thread.

The thread is subsequently hardened with a 10% solution of formaldehydeand is then washed and dried at a moderate temperature. Hardening maytake place immediately after spinning or at a later stage. The productis flexible and has a strength which even exceeds that of sheeps wool.

ple II Casein obtained from skim milk is dissolved in 14% ammonia waterto form a 16% casein solution. This solution is spun at 45 C. in aspinning bath containing 10% by weight of sodium sulphate, 10% by weightof zinc sulphate, 3% by weight of sulphuric acid and 3% by weight ofcresol sulphonic acid.

The initial tension which may be applied to the thread in the spinningprocess if the abovementioned sulphonic acid is employed in the spinningbath is greater than that which can be used if the sulphonic acid is notpresent. This increased tension results in an increased rate ofspinning.

What I claim is:

l. A process for the production of proteincontaining artificial threads,filaments, bands and the like, which comprises extruding a solution ofan alkali salt of a protein into an acid precipitating bath containingat least one substance selected from the group consisting of aromaticand hydroaromatic acids and the condensation products of aromatic andhydroaromatic sulphonic acids with aldehydes, for exerting a glueprecipitating action and for tanning the formed product, tensioning saidproduct while in said bath and finally treating the product with ahardening agent.

2. A process for the production of proteincontaining artificial threads,filaments, bands and the like, which comprises extruding a solution ofan alkali salt of a protein into an acid precipitating bath containingat least one substance selected from the group consisting of arcmaticand hydroaromatic acids and the condensation products of aromatic andhydroaromatic sulphonic acids with aldehydes, for exerting a glueprecipitating action and for tanning the formed product, tensioning saidproduct while in said bath and finally hardening the product bytreatment with an aldehyde.

3. The process as defined in claim 2 wherein the substances contained inthe precipitating bath are in an unpurified state.

4. A process for the production of proteincontaining artificial threads,filaments, bands and the like, which comprises extruding a solution ofan alkali salt of casein into an acid precipitating bath containing atleast one substance selected from the group consisting of aromatic andhydroaromatic acids and the condensation products of aromatic andhydroaromatic sulphonic acids with aldehydes, for exerting a glueprecipitating action and for tanning the formed product, tensioning saidproduct while in said bath and finally hardening the product bytreatment with an aldehyde.

5. A process for the production of proteincontaining artificial threads,filaments, bands and the like, which comprises extruding a solution ofan alkali salt of a protein into an acid precipitating bath containing acondensation product of an' aromatic sulphonic acid and an aldehyde, foreverting a glue precipitating action and for tanning the formed product,tensioning said product while in said bath and finally hardening theproduct by treatment with formaldehyde and the like.

6- A process for the production of proteincontaining artificial threads,filaments, bands and the like, which comprises extruding a solution ofan alkali salt of a protein into an acid precipitating bath containing acondensation product of an hydroxy aromatic sulphonic acid and analdehyde, for exerting a glue precipitating action and for tanning theformed product, tensioning said product while in said bath and finallyhardening the product by treatment with formaldehyde and the like.

'7- A process for the production of proteincontaining artificialthreads, filaments, bands and the like, which comprises extruding asolution of an alkali salt of a protein into an acid precipitating bathcontaining the condensation product of cresyl sulphonic acid andformaldehyde. for exerting a glue precipitating action and for tanningthe formed product,tensioning said product while in said bath andfinally hardening the lpioduct by treatment with formaldehyde and the 8.A process for the production of protein-containing artificial threads,filaments, bands and the like, which comprises extruding a solution ofan alkali salt of a protein into an acid precipitating bath containing ahydroaromatic sulphonic acid, for exerting a glue precipitating actionand for tanning the formed product. tensioning said product while insaid bath and finally hardening the product by treatment withformaldehyde and the like.

9. A process for the production of protein-containing artificialthreads, filaments, bands and the like, which comprises extruding asolution of an alkali salt of a protein into an acid precipitating bathcontaining an oxyhydroaromatic sulphonic acid, for exerting a glueprecipitating action and. for tanning the formed product, tensioningsaid product while in 'said bath and finally hardening the product bytreatment with formaldehyde and the like.

10. A process for the production of proteincontaining artificialthreads, filaments, bands and the like, which comprises extruding asolution of an alkali salt of a protein into an acid precipitating bathcontaining cyclohexanone-sulphonic acid, for exerting a glueprecipitating action and for tanning the formed product, tensioning saidproduct while in said bath and finally hardening the product bytreatment with formaldehyde and the like.

- 11. A process for the production of proteincontaining artificialthreads, filaments, bands and the like, which comprises extruding asolution of an alkali salt of a protein into an acid precipitating bathcontaining an aromatic sulphonic acid, for exerting a glue precipitatingaction and for tanning the formed product, tensioning said product whilein said bath and finally hardening the product by treatment withformaldehyde and the like.

12. A process for the production of proteincontaining artificialthreads, filaments, bands and the like, which comprises extruding asolution of an alkali salt of a protein into an acid precipitating bathcontaining an aromatic monosulphonic acid, for exerting a glueprecipitating action and for tanning the formedproduct, tensioning saidproduct while in said bath and finally hardening the product bytreatment with formaldehyde and the like.

13. A process for the production of proteincontaining artificialthreads, filaments, bands and the like, which comprises extruding asolution of an alkali salt of a protein into an acid precipitating bathcontaining cresyl sulphonic acid, for exerting a glue precipitatingaction and for tanning the formed product, tensioning said product whilein said bath and finally hardening the product by treatment withformaldehyde and the like.

THEODOOR KQCH.

